Traffic markings convey information to drivers and pedestrians by providing exposed visible, reflective, colored and/or tactile surfaces that serve as indicia. In the past, such a function was typically accomplished by painting a traffic surface. Modern marking materials offer significant advantages over paint such as dramatically increased visibility and/or reflectance, improved durability, and temporary removable marking options. Examples of modern pavement marking materials are thermoplastic, pavement marking sheet materials, tapes and raised pavement markers.
Danger exists to motorists in that changes in surface temperature may promote the formation of slippery surfaces, most notably ice. Motorists driving on roadways many times forget that bridge surfaces freeze sooner than roadways that are in contact with solid surfaces. The coefficient of friction of the roadway changes as soon as the surfaces change. (for example from roadway to bridge surface)
Black ice, also called glare ice or clear ice, is a thin layer of ice on the roadway that is created by relatively large droplets of water that slowly freeze at the freezing point of water. The larger droplets have a longer time to bond to the road or bridge surface forming a solid, icy surface.
Any ice is dangerous to drive on because it's so slippery, but black ice is especially insidious because a road covered with it looks merely wet, not icy. Black ice isn't really black, of course, but it's so thin and transparent that the dark color of the pavement shows through, and it is extremely dangerous to drive on such a surface. Statistics from Sweden show that the automobile accident rate there is five times higher on roads covered with black ice than on dry pavement, four times higher than on wet pavement, and twice that as on pavement covered with packed snow.
There is, therefore, a need for a roadway surface marking that will convey the potential for ice formation not only to alert motorists, but as advanced notification to public works crews to encourage the application of anti-icing and/or deicing materials.